1. Field of the Disclosure
The present disclosure relates to a pressure detection device, and an intake pressure measurement apparatus which measures an intake pressure of an internal combustion engine using the pressure detection device.
2. Description of the Related Art
Japanese Unexamined Patent Application Publication No. 2000-162075 discloses an intake pressure measurement apparatus which measures the pressure of an intake channel of an internal combustion engine.
The intake pressure measurement apparatus has two chambers which are partitioned to have a concave shape in a main housing. A pressure sensor chip which is a pressure detection element is fixed in one chamber, and the pressure sensor chip is covered with protection gel. An IC package which is a signal processing element is fixed in the other chamber.
A cover which covers the two chambers of the main housing is provided, and a pressure introduction pipe which introduces the pressure of the intake channel of the internal combustion engine is formed integrally in the cover. The pressure introduction pipe faces the pressure sensor chip, and the pressure of the intake channel is detected by the pressure sensor chip.
As described in Japanese Unexamined Patent Application Publication No. 2000-162075, in this kind of intake pressure measurement apparatus, since a metallic lead frame is buried in the main housing, thermal strain is likely to be applied to the pressure sensor chip due to the difference in thermal expansion coefficient between the lead frame and the main housing.
When the main housing is used in combination with a cover which is a casing, mechanical stress, such as fastening force or vibration, is often applied to the main housing.
In the structure described in FIG. 2 of Japanese Unexamined Patent Application Publication No. 2000-162075, the pressure sensor chip is disposed close to the outer wall side in one chamber of the main housing. For this reason, strain which is generated in the main housing due to thermal stress or mechanical stress is likely to directly act on the pressure sensor chip. Strain which is applied to the pressure sensor chip becomes disturbance other than change in pressure, making it impossible to accurately measure the intake pressure.
These and other drawbacks exist.